The present invention relates to a high speed serial printer.
In serial printers known heretofore, an input encoder produces print signals, which order the printer to print a specified character, and carriage space and line feed signals which order the printer to move a printing head left or right or the paper up or down relative to the printing head. Typical carriage space signals include forward space (right), backspace (left) and carriage return. These prior art printers execute each instruction as it is received, even if several carriage space or line feed signals are produced between consecutive print signals. In order to print a column of one-digit numbers in the middle of a page, for example, after a first number is printed the carriage drive mechanism automatically right spaces the printing head by one space in preparation for printing the next character. However, since the next character is to be a number below rather than to the right of the first number, this space operation is unnecessary. After allowing sufficient time for the completion of the right space operation, a carriage return and line space operation is executed so that the printing head is moved to the leftmost character position. After this operation is completed, the printing head is multiple spaced rightwardly to the position which it occupied originally to print the second number.
Since the final position of the printing head is the same as its original position, the right space, carriage return and multiple right space operations constitute totally wasted time since all that was actually required was a single line feed operation. In addition to unnecessarily reducing the speed at which the printer produces useful copy to a highly significant extent, these useless operations increase the noise level of the printer and reduce its service life.